First (Possibly Failed?) Hamon

E

Erik Nenzen

Joined
Jan 6, 2016
Messages
18
I was bitten by the knife bug about a year ago and started making knives around then, but I only recently decided to try a hamon. I applied the "clay" (Commercial grade quikrete fireplace mortar) that I got at home depot, I let it dry for 36 hours, and I quenched it like I normally do. I am using 1084 (I know this isn't the best steel for a hamon but this is the best I have available) that I purchased from Knifemaker.ca. After cleaning off most of the clay remnants and oil left on the blade, I tested the blade with my brand new grizzly hrc files and the spine was WAY softer than the edge. I stuck it in my toaster oven at 400 degrees for an hour and test the hardness with my files and it was the exact same. After roughly another hour I tested it and still had the same results. I think I am at 3 hours now and my 65 hrc file still skates on the edge like it just came out of the oil. By now the edge almost looks purple while the flat of the blade is straw colored. I can see one of three things that could be happening; my files could be junk, I could be going insane, or something way beyond my limited metallurgical knowledge happened as the blade was quenched. I have only had this happen to one other blade before and I kind of just gave up on that one because I thought it was just some weird occurrence. I would appreciate any help that you guys can provide as I have no idea what to do in this situation. If possible, I would prefer to not heat treat it again because I have difficulties keeping the clay on the blade during the process. Anything helps.

PS: I will try to include a link to some ugly photos of what I am talking about, but if it doesn't work or if you can see all of my photos on google drive please let me know. Also, is it normal to see the exact shape the clay was in without doing much hand sanding?

Thanks,
Erik Nenzen

https://drive.google.com/file/d/0B1a2ctiSJAqrRU1WVW0tb2swR28/view?usp=sharing
https://drive.google.com/file/d/0B1a2ctiSJAqrQnBJV1lvX3FfbWc/view?usp=sharing
 
Welcome to the forum.

The clay will leave a mark like that right out of the quench, you just have to grind through all the decarb to get to the real hamon.

As for the hardness files, I don't know much about them. However, if you tempered at 400 degrees your knife will be well below 65 hrc.
 
The files are useless for getting a specific hardness. My guess is that your blade is fine.

Sand it back down to remove all the decarb and scale, then sand to 400 grit. Once flat and smooth, etch in FC diluted 5:1. That should show the actual hamon.

The photos show the protected steel that is softer than the hardened ( and discolored) steel. You have to sand into both to get the real surface. When you etch the blade, the hardened steel will usually etch darker than the soft steel. While the pattern looks quite dramatic now, it is always a surprise to see what it actually is. Hope your turns out good.

On 1084, which has a fairly good amount of manganese, it is generally a better idea to do a suguha hamon than a choji hamon, as you did. The ambling curved line forms better than the teeth in a steel like 1084. In 1095 and W2, the pattern can be much more bold. On steels like Hitachi white #1 and its Takefu equivalent, you can get amazing details.
 
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Thank you so much! I really had no idea what would be the best option. Right now I think I will continue throught with the knife and use it as much as possible to see whether or not I like the result and whether the files can be trusted. I would love to start using some of the steels mentioned and intend to when we build a kiln hopefully in a couple months. Right now I'm using the fire pit and magnet technique. :)

Thanks again,
Erik Nenzen
 
The best thing to do with those test files is clean up the edge a bit after tempering and run down them from 65 to 60 to 55. Feel how the three bite different. The 1084 blade should be around Rc 59 with a 1475 austenitization, a sufficient oil quench ( a gallon of canola), and a 400F temper. The files will tell you what that feel and sounds like. Don't file too much, because those test files have a very limited use life.

Here is what I do as a backyard HT and testing when that is all I have available.
1) I do the HT the best I can with what is available. - usually a forge, a magnet to find 1440F, a warm canola oil quench, and a set of 400F tempers in a kitchen oven.
2) I clean up the blade by grinding/sanding back the edge a few thousandths and knocking down the bevels to good shiny steel. Usually, I use 120 grit for this. That should get rid of any decarb along the edge.
3) I take a fairly new file ( Nicholson or similar) and file at a 45 degree angle ( on both planes) down the edge in one long stroke. It should sing a high pitched note. If it bites deeply, or makes a dull sound, the HT isn't right.

To get a comparison of what the sound should be, dull the edge of a known hardness carbon steel knife and try the same file on it.
 
Thanks for the recomendation! Should the Nicholson file skate on the steel even after tempering? Up until now I just assumed it wouldn't and never even bothered to try. Roughly how long do the HRC files normally last and is there any way to prolong their life by grinding down the tip whilst keeping it cool or something along those lines?
 
It skates like it was on glass right after the quench. It bites a bit more, but still doesn't file away any metal after tempering.
 
Thanks for the help! I completed the satin finish tonight and will be working on some handles soon, and pictures will be included of course. I have heard that the best way to etch it is to completely finish the knife, de-grease it, and then etch the whole thing with the g10 handles on. Would you recommend this, and this there a better altenative? I would love to shape the scales, unscrew them, etch the blade, and then re-attach them, but I will be using pins for this one so that isn't an option.:(
 
If you're trying to develop the hamon don't etch it wil the handles on as it takes many cycles of etching and polishing before you'll get your hamon where you want it. Finish the front of the scales to 100% complete. you can temporarily attach the scales with a couple drops of super glue and then remove them, develop the hamon, glue the scales, and be done.
 
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